Sutton and East Surrey Water (SES) knew that supplies to the UK's second-busiest airport could run dry a day in advance but did not pass on the information, airport bosses claimed. However, the airport only became aware of the problem when its water pressure began to drop on Sunday morning. Gatwick only became aware of the problem when its water pressure began to drop on Sunday morning - Aaron Chown/PAA Gatwick spokesman said: "We understand SES Water became aware of the water outage several hours before the airport. Our first awareness of the situation was when on-site water pressure dropped. Gatwick began losing water pressure at 10am on Sunday, forcing the airport to draw on emergency reserves.